C1 Structure & Function Of The Processor And Types Of Processors

Question 1

What is a control unit?

Answer 1

Coordinate other components activity

Question 2

What is the ALU?

Answer 2

The problem solving part of the CPU

Question 3

What is a register?

Answer 3

Block of memory that stores instructions

Question 4

What are buses?

Answer 4

Series of connectors transfer signals between internal components

Question 5

What is MAR?

Answer 5

Holds the address in memory and tell where to fetch/store data from/to

Question 6

What is a hard drive?

Answer 6

Type of data storage device used in laptops and desktop computers

Question 7

What is a memory unit?

Answer 7

Stores currently running programs and data

Question 8

How do the number of cores affecting the CPU performance?

Answer 8

• each core process different instructions at the same time with own FDE cycle
• however software may not take full advantage of all the processors available

Question 9

How does the clockspeed effect the CPU performance?

Answer 9

• regular on/off signal syncs the operations of processor components
• actions each take a fixed number of cycles to complete

Question 10

How does cache memory affect the CPU performance?

Answer 10

• level 1 cache split into instruction cache and data cache so that they can be fetched simultaneously
• more cache = more likely data won’t be fetched from RAM
• already loaded into super fast cache memory where they can be retrieved quickly

Question 11

What is pipelining?

Answer 11

One instruction is being fetched while the next one is being decoded and the other executed

Question 12

What are the limitations to pipelining?

Answer 12

You can’t predict which instruction will be fetched next

Question 13

What is branch prediction?

Answer 13

A digital circuit try to guess which way branch will go before known definitively
- essential part of modern CPU
- hardware: BPU
- BPU predicts which branch will be chosen with high confidence given current encoded instruction
- where significant improvement comes from from in latest processors

Question 14

What is Von Neumann Architecture?

Answer 14

Instructions and data stored in common main memory and transferred using single shared bus

Question 15

What are the advantages to Von Neumann?

Answer 15

• simplified design of CPU
• data from memory and devices accessed in same way
• all generation purpose computers are VN principle

Question 16

What are the uses for Von Neumann?

Answer 16

• PC, laptops and servers
• data and instructions share the same memory and use the same word length
• one bus = bottleneck

Question 17

What is Harvard Architecture?

Answer 17

Separate buses for data and instructions so the data and instructions are no longer competing for the same bus

Question 18

Uses of Harvard architecture?

Answer 18

• different word length use for data and instructions
• specialised embedded systems and digital signal processing
• control unit with 2 buses = complex and costly

Question 19

What is in the fetch phase in the FDE cycle?

Answer 19

1. Address of next instruction copy from PC ago MAR
2. Instruction in MAR copy to the MDR
3. PC contents increment by 1
4. MDR content copy to CIR

Question 20

What is involved in the decode stage of FDE cycle?

Answer 20

5. Instructions in CIR decoded
6. Split into opcode and operand which can determine the instruction type and additional data fetched from memory
7. Pass to ACC

Question 21

What happens in the execute phase of the FDE cycle?

Answer 21

8. Instruction is executed and the results held in ACC or stored in memory

Question 22

What is involved in the systems bus?

Answer 22

The system of the data, control and address bus

Question 23

What is data bus?

Answer 23

Transport data between components

Question 24

What is the control bus?

Answer 24

Carries the commands

Question 25

What is the address bus?

Answer 25

Only goes from memory to CPU and transmit memory address specify where data sent or retrieved from

Question 26

What is RISC processors?

Answer 26

- simple instructions - fewer instructions - fewer addressing modes - only load and store instructions can access memory - processor hardware more simple

Question 27

What is CISC processors?

Answer 27

- complex instructions ( normally made of simple instructions) - large range of instructions - many addressing modes - many instructions access memory - processor more complex

Question 28

What are parallel systems?

Answer 28

- 2 processors work together to perform single task - task split into small sub tasks - any task can be processed by any of the processors - decreased time takes to execute programs, software specifically written to take advantage of multi core system

Question 29

What is MISD?

Answer 29

- multiple processors - different set instructions on some set of data

Question 30

What is SIMD?

Answer 30

- multiple processors follow same set of instructions - process different data concurrently

Question 31

What is MIMD?

Answer 31

- multiple processors - process instructions independently of others - most common is desktop computers

Question 32

What are co-processors?

Answer 32

Like parallel processing but the additional processor responsible for carrying out specific task

Question 33

What are the advantages to multicore systems?

Answer 33

- more jobs done in short amount of time - task shared means the workload is reduced in individual processors

Question 34

What are the disadvantages to multicore systems?

Answer 34

- difficult to write programs for multi core systems - not all tasks can be split across multiple processors

Question 35

What are GPUs?

Answer 35

-Type of processor - perform complex calculations to render graphics - located on a separate graphics card - run faster - cost efficient on CPUS

Question 36

What are the uses of GPUS?

Answer 36

- medical and scientific research - oil and gas exploration - financial modelling

Question 37

What is Little Man Computer?

Answer 37

Simple architecture designed to help understand concept of machine code and instruction sets